A quantitative study of bioenergetics in skeletal muscle lacking carbonic anhydrase III using 31P magnetic resonance spectroscopy
| Autor: | Krista Vandenborne, R. E. Forster, Neeti Pathare, Min Liu, Glenn A. Walter |
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| Rok vydání: | 2006 |
| Předmět: |
Male
medicine.medical_specialty Magnetic Resonance Spectroscopy Intracellular pH Oxidative phosphorylation Creatine Phosphocreatine chemistry.chemical_compound Mice Adenosine Triphosphate Internal medicine medicine Animals Muscle Skeletal Mice Knockout Multidisciplinary ATP synthase biology Skeletal muscle Hydrogen-Ion Concentration Biological Sciences Carbonic Anhydrase III medicine.anatomical_structure Endocrinology chemistry biology.protein Creatine kinase Female Energy Metabolism Adenosine triphosphate |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America. 104(1) |
| ISSN: | 0027-8424 |
| Popis: | Oxidative slow skeletal muscle contains carbonic anhydrase III in high concentration, but its primary function remains unknown. To determine whether its lack handicaps energy metabolism and/or acid elimination, we measured the intracellular pH and energy phosphates by 31 P magnetic resonance spectroscopy in hind limb muscles of wild-type and CA III knockout mice during and after ischemia and intense exercise (electrical stimulation). Thirty minutes of ischemia caused phosphocreatine (PCr) to fall and P i to rise while pH and ATP remained constant in both strains of mice. PCr and P i kinetics during ischemia and recovery were not significantly different between the two genotypes. From this we conclude that under neutral pH conditions resting muscle anaerobic metabolism, the rate of the creatine kinase reaction, intracellular buffering of protons, and phosphorylation of creatine by mitochondrial oxygen metabolism are not influenced by the lack of CA III. Two minutes of intense stimulation of the mouse gastrocnemius caused PCr, ATP, and pH to fall and ADP and P i to rise, and these changes, with the exception of ATP, were all significantly larger in the CA III knockouts. The rate of return of pH and ADP to control values was the same in wild-type and mutant mice, but in the mutants PCr and P i recovery were delayed in the first minute after stimulation. Because the tension decrease during fatigue is known to be the same in the two genotypes, we conclude that a lack of CA III impairs mitochondrial ATP synthesis. |
| Databáze: | OpenAIRE |
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